core/include/core/utils/HashedString.hpp

#ifndef CORE_HASHED_STRING_HPP
#define CORE_HASHED_STRING_HPP

#include <string.h>

#include "core/utils/Types.hpp"

namespace Core {
    struct StringHash {
        i32 length = 0;
        u32 hash = 0;
    };

    constexpr StringHash hashString(const char* s) {
        StringHash h;
        while(*s != '\0') {
            h.length++;
            h.hash = 2120251889u * h.hash + static_cast<u32>(*(s++));
        }
        return h;
    }

    template<i32 N>
    class HashedString {
        static_assert(N > 0, "length of hashed string must be positive");
        StringHash hash;
        char data[static_cast<u32>(N)];

    public:
        HashedString() : hash() {
        }

        HashedString(const char* s) : hash(hashString(s)) {
            strncpy(data, s, N);
        }

        bool operator==(const HashedString& other) const {
            return hash.length == other.hash.length &&
                   hash.hash == other.hash.hash &&
                   strcmp(data, other.data) == 0;
        }

        bool operator!=(const HashedString& other) const {
            return !(*this == other);
        }

        i32 getLength() const {
            return hash.length;
        }

        constexpr i32 getCapacity() const {
            return N - 1;
        }

        u32 hashCode() const {
            return hash.hash;
        }

        operator const char*() const {
            return data;
        }
    };
}

#endif